An image apparatus may not actually comprise all of the image data. Instead, the image apparatus may be an image client that only obtains certain views of the image data from an image server. The image client and the image server may together form a system that allows the user to navigate through the image data by obtaining the views from the image server in dependence on navigation requests of the user, and displaying the views on the image client. During use, the obtained views of the image data constitute less data than all of the image data. Therefore, the system may enable an image client to navigate through the image data, without a need for the image client to obtain or locally store all of the image data.
The above system, however, may suffer from a latency, i.e. a delay, between a user requesting a view and the image client being able to display the view. In particular, the latency may occur during the period of obtaining the view from the image server.
A PhD thesis entitled “OptiStore: An On-Demand Data Processing Middleware for Very Large Scale Interactive Visualization” by Chong Zhang, submitted to the University of Illinois at Chicago, 2007, discloses a client that runs a visualization application and is connected to a data repository comprising a three-dimensional image data set. The client is arranged for minimizing a data access latency of the visualization application to the data set. For that purpose, a main controller receives view information and data requests from the visualization application. The view information relates to, e.g., a position of a viewpoint. The main controller then checks whether the requested data exists in a cache. If it exists, the cache returns the data to the visualization application; otherwise, it passes the view information to a predictor. Based on a history of the view information, the predictor creates a data request. Finally, once the requested data arrives from the data repository, it is stored in the cache. Hence, the main controller reduces the latency of the visualization application by predicting future data requests from a history of the view information.
A problem of the main controller is that it insufficiently reduces a latency that occurs while navigation through image data on an image client takes place.